U.S. patent application Ser. No. 381,434 entitled "Phosphorus-Containing Squalene Synthetase Inhibitors and Method", filed concurrently herewith discloses phosphorus-containing squalene synthetase inhibitors which are useful in inhibiting cholesterol biosynthesis including those of the structure ##STR3## wherein R.sup.2, R.sup.3, and R.sup.4 are H, metal ion, or lower alkyl and Y.sup.1 and Y.sup.2 are H or halogen. These compounds may be prepared starting with the phosphonic acid ester II ##STR4## wherein R.sup.2 is C.sub.1 to C.sub.8 alkyl or C.sub.3 to C.sub.12 alkenyl.